Internet Architecture: Lessons Learned and Looking Forward

Abstract

This chapter explores the architectural design of the Internet. The main objectives are: (i) highlight the design principles underlying the Internet architecture and explain their roles in the success of the network, and (ii) identify some of the limitations of the current Internet architecture and present a possible approach to addressing them. 1. Introduction In this chapter, we explore the architectural design of the Internet. We believe that a historic perspective is essential for this exploration. Many important lessons about network design can be learned from the evolution of the Internet architecture. The Internet had a very modest start, borne out of an experimental network with a handful of nodes in the late 1960s. There was no comprehensive theory about packet network design in place at the time. It was not until a dozen or so years later, when the Internet had already become a network with about 100,000 nodes that the broad research community started to realize that several early design choices made for the Internet architecture, with an emphasis on simplicity , had played a crucial role in its growth and robustness. (Clark88) In other words, it is not by accident that the basic elements of the Internet architecture have withstood the test of time for over three decades, creating the one and only global data networking infrastructure in the process; several architecturally profound design principles were at work. In the first half of the chapter, which includes Sections 2, 3, and 4, we will try to expose as many key points of these design principles as possible while describing nuts and bolts of the Internet architecture. Examining the Internet architecture from a historic perspective would not be complete without pondering the future of the Internet architecture. In the second half of the chapter, we pose and try to answer the following question: Has the current Internet architecture reached the end of its historical role? To put the question another way: Is a clean-slate design of Internet architecture necessary in order to meet all emerging requirements? We first provide a holistic view of the current Internet architecture based on its division of core functionality into three planes: data, control, and management. We then discuss why the Internet control and management planes have fundamental limitations in coping with several emerging service requirements and why a completely new approach to network control and management may be required. Finally, we describe the 4D network architecture (Greenberg05a,b), which is an instance of a clean slate design of Internet architecture.